Magnetic Induction Signal Repeater

1. A magnetic induction (MI) repeater comprising: first and second coils configured to have the same resonance frequency and to be substantially isolated from one another; and an amplifier connected to the first and second coils and configured to receive a signal induced in the first coil by a first magnetic field and output, via the second coil, a second magnetic field based on the signal, wherein the second magnetic field is amplified relative to the first magnetic field.

2. The repeater of claim 1 , wherein the first and second coils are concentric.

3. The repeater of claim 2 , wherein the first coil is disposed in a first plane and the second coil is disposed in a second plane orthogonal to the first plane.

4. The repeater of claim 1 , wherein the respective centers of the first and second coils are disposed on the same axis.

5. The repeater of claim 4 , wherein the first coil is disposed in a first plane and the second coil is disposed in a second plane orthogonal to the first plane.

6. The repeater of claim 1 , further comprising: a detection circuit configured to activate the amplifier upon detecting the presence of an MI signal via at least one of the first and second coils.

7. The repeater of claim 6 , wherein the detection circuit comprises radio signal strength indication (RSSI) circuitry monitoring the first and second coils.

8. A system comprising: first and second devices, each having at least one coil and each configured to communicate using magnetic induction (MI); and an MI repeater comprising: first and second coils configured to have the same resonance frequency as one another and to be substantially isolated from one another; and a first amplifier connected to the first and second coils and configured to receive a first signal induced in the first coil by a first magnetic field output by the first device and output, via the second coil, a second magnetic field based on the first signal so as to induce a second signal in the coil of the second device, wherein the second magnetic field is amplified relative to the first magnetic field.

9. The system of claim 8 , wherein the first amplifier is further configured to receive a third signal induced in the second coil by a third magnetic field and output, based on the third signal, a fourth magnetic field via the first coil, wherein the fourth magnetic field is amplified relative to the third magnetic field.

10. The system of claim 8 , wherein the MI repeater further comprises: third and fourth coils configured to have the same resonance frequency as one another and to be substantially isolated from one another; and a second amplifier connected to the third and fourth coils.

11. The system of claim 10 , wherein the MI repeater further comprises: radio signal strength indication (RSSI) circuitry configured to monitor the first, second, third and fourth coils; logic circuitry configured to activate one or more of the first and second amplifiers upon detection of an MI signal via one of the first, second, third and fourth coils.

12. The system of claim 11 , wherein the first coil is disposed in a first plane and the second coil is disposed in a second plane orthogonal to the first plane.

13. The system of claim 12 , wherein the first and second coils are concentric.

14. The system of claim 10 , wherein the third coil is disposed in a third plane orthogonal to the first plane and the fourth coil is disposed in a fourth plane orthogonal to the second plane.

15. The system of claim 8 , wherein second device is a medical device.

16. A method of operating a magnetic induction (MI) repeater including an amplifier connected to first and second coils that are substantially isolated from one another and are configured to have substantially the same resonance frequency, the method comprising: providing to the amplifier a first signal induced in the first coil by a first magnetic field; and outputting, via the second coil, a second magnetic field based on the first signal using the amplifier, wherein the second magnetic field is amplified relative to the first magnetic field.

17. The method of claim 16 , wherein the first and second coils are concentric.

18. The method of claim 17 , wherein the first coil is disposed in a first plane and the second coil is disposed in a second plane orthogonal to the first plane.

19. The method of claim 16 , further comprising: activating the amplifier upon detecting the presence of an MI signal via at least one of the first and second coils.

20. The method of claim 16 , further comprising: providing to the amplifier a second signal induced in the second coil by a third magnetic field; and outputting, via the first coil, a fourth magnetic field based on the second signal using the amplifier, wherein the fourth magnetic field is amplified relative to the third magnetic field.